Down pressure control systems can control the pressure based on feedback from a sensor measuring the pressure on the planter gauge wheels. For example, a farmer might set the system to keep 200 lbs of force on the gauge wheels. Then a controller increases or decreases the force from the row unit down pressure actuator so as to try to maintain the force at that set point.
Farmers frequently are confused about what the correct set point is for down pressure control. Is lighter better? There are arguments for this because an excessively compacted furrow can make it harder for the roots to grow and even result in the dreaded “Mohawk roots” where the roots grow along the length of the furrow instead of out and down. Too little sidewall compaction can also be a problem because insufficient firming of the soil in some soil conditions can result in an inconsistent vee shape to the furrow resulting in inconsistent seed placement because the vee is intended to collect the seed at the bottom of the vee. Insufficient firming can result in a furrow that falls in on itself.